1. Field of the Invention
The present invention relates to the field of devices for clearing clogged drains, most particularly devices that are hand operated and exert pressure on the obstruction.
2. Description of the Related Art
U.S. Pat. No. 4,566,139 relates to a piston plunger having a suction cup and a handle with a piston positioned inside. When the handle is pressed downward, the air trapped beneath the suction cup can escape upward through a vent provided into the handle, forcing the piston upward. The piston eventually drops down under its own weight, and the trapped air escapes through a vent in the handle.
U.S. Pat. No. 4,445,236 relates to a reversible plunger and pump apparatus that includes a vacuum cup positioned at one end of a handle and a reversible electric driven pump that operates through the suction cup.
U.S. Pat. No. 2,697,842 relates to a combination hand and air force pressure pump and plunger which includes a piston positioned within a cylinder having a plunger bell reversibly mounted on one end thereof and couplings for optional connection to a pressurized air source.
U.S. Pat. No. 1,684,880 relates to a combined suction and force pump designed for cleaning stop drains, bowls, and toilets that includes a hand operated piston positioned within a handle portion having a flexible bell shaped sealing cup and integral sleeve secured thereto.